Fix return type of load_intensity_cal_file and save_intensity_cal_file in .h

src/CCDSpectrometer.h

@@ -144,8 +144,8 @@ public:
 	int exposures[AUTO_EXPOSURE_MEAN];
 	int exposure_idx;
 	void string_explode(string str, string separator, vector<string>* results);
-	int load_intensity_cal_file(string filename);
-	int save_intensity_cal_file(string filename);
+	void load_intensity_cal_file(string filename);
+	void save_intensity_cal_file(string filename);
 	uint32_t myntohl(uint32_t val_l);
 
 	float fit[5/*NR_WAVELEN_POL_COEF*/];